Synchronous converter.



v S. H. MARTIN. SYNCHRONOUS CONVERTER. APPLICATION FILED AUG. 22, 1912.

Patented Feb. 8, 1916.

. UNITEI? To all 'wimm canoe Be it kiimvii that i citizen of ihe United 5 iiaiies iii ehreiieus (fenvoitage with inei'enis in'lpi'evoii n'iezms in? ii UjJi-El'aii with e pewe unity; to provide im Y meeting She usual iiehi \'iii cessive induced wk-age (,iUOIHiHS (iilllVQiilUi' of ifhis 1 pruveii, form of COilSili'iiCtifiD e screen and (hamper imii i0 piiwiiie an in proved system of "v'iiliililgS en :1 magnetic screen in such hummer x m.

ieguhi'te pi'eveiiiz under hind.

A specific constructien ii imam-hung ii is ventieh is ehmx'n in Che QU'TCUEME'JDL i i Tings,

voltage v. a Figure l M ii dnigrzimmziile and new 01 an "fiiilfiiiii, current eon umiiiiiumiri inugggnelie 5-1:: sti'ueui'eiiy ceiiihhieii tween the 'ieie ii mzw; oi? the rotor, the eeri ii heii winding 01' iiinii'ngii en the position and mam imagine; 1mm

therein under "iilylii fi eeiii ii 115 of speed voltage and loud, i 2 1H we:

tion 03 file seine taken 01.

i Fig. 5 it sec'iiio the line L 5 I a wiiiieii em i; we mag etie screen 01' e JiiiHiei: 1 is p'i'eviiieci i'i series of saints opemiii which Wiii h inui'tes doseiih The screen is; huiiis up 01 mini m'zei, fringe "hid mounted in 6 end 1' 'ihe whole iHUO U116 integral ubl'i ifiiiiiie by means if embedded copper rivets m: hnhfis which are placed {LS near inner surface '01? the screen as good inechiiiiieii LOiiStlllQiiOil Wiii permit. The external elm-Jed sm'i ace of the screen 1 is 1 xi er machined ii finCiiS eiiiin'ziceii v i A v a neid. in phzee by sh pole IHCQS me, 7

H of Ehe i L i; me. An air @131 J L en the inner: surface n L "iidwliy beiweeii the ion? was 12. i3, ei

. V l i i. 1 1 1) ,Q in win 0i 'ieim wound 00119 L which exitemi 1 41 1 I A h: and eceupy we 51453210 031? smuhei' slots in.

im 1 i v 4 11 i W W 11") inu hihiiui n10, ml 1141M PO (5 u ,U i

H 15 prowiied ior by shunt field wind- 22 wind A connected in i'ehiwiih mie iiimthesb. 'ihe magi (hair-tum "iii the 12mm field poies and mine euppie poles 3.1 on the screen 1121;; is iieed by eonnmriwy n SQXWS across the i-iiizeiit MHfiiiQi-i the fiehi (3011:; 2355 and iihe fox-iii wound cmis the ioi'in wound emis being; conn cted in "mince ihe HOiiiiliY as that I): faces. 'ihe puiui' peies mid zhe (hi-each:

e sex'ei'iii main in the seven 1 miigne'tiu vireuite iEHiiUt'iUHi by ietters N n C3 and by :-1 News, 21%;) miixeiy on Fig. 1.

ii in one I)" the (:0 ieistive eoniii'ai mini be a being; s

valuescorresponding to an angular displacement of 120 degrees or the three phase relation. Direct current brushes 27, 28, 29 and 30 are equally spaced upon and coact with the direct current commutator 23. Alternate brushes are of like polarity and may be connected in pairs, as indicated in Fig. 1. A variable resistance 32 is connected in series with the field coils 21 and 22 for regulating the field strength.

The arrangement of the windings 011 the screen 1 is preferably in the following form:

The form windings 21 are arranged in a series of pairs spaced apart circumferentially around the screen 1, each of the coils 21 in each pair being of different polarity from its mate and the windings having the same polarity being placed adjacent to each other so that the north pole of one pair will be adjacent the north pole of the next adjacent pair, and the south pole of a given pair will be adjacent the south pole of the next adjacent pair, and so on; the ring windings 17, 18, 19 and 20 being respectively interposed between the form windings 21 com posing each of the series of pairs in their order around the screen 1, and the said form windings being so arranged that the two poles of like polarity in each group of two adjacent pairs with respect to the main field windings, will be positioned adjacent a field winding of like polarity. The polarity of both the form windings and the ring windings is the same as the adjacent main poles.

In the operation of the machine in transforming polyphase alternating currents into direct currents, connection between the alternating current supply 31 and the. three slip rings 2 1, 25, and 26 may be closed directly through the switch 33. By reason of construction and the polyphase connection of the alternating current circuit to the rotor, the current is distributed to produce in the rotor 10 a 'rotating magnetic field. Since the rotor 10 is surrounded by the closed magnetic ring or screen 1 (having closed induction current circuits) the starting action will be similar to the usual polyphase induc ion motor, in which, how-- ever, the squirrel cage wound element usually rotates. The squirrel cage element comprising the bar conductor 1 and the connecting end plates 3 in this device is stationary, but the starting characteristic is. dependent only upon the relative rotation of the elements.

The continuous current output is conducted from the rotor 10 by means of the four brushes 27, 28, 29 and 30, and the localization of the magnetic poles on the screen 1 is in part provided by a circuit, starting from brush 29 to the variable resistance 32, thence through the shunt field coils 22, thence through the form wound coils 21, thence to brush 28. The shunt wound coils 22 produce the four poles 5, 6', 7' and 8' of alternate polarity and the form wound coils 21 produce the supplementary poles of the same polarity as the adjacent main poles. The series coils 17, 18, 19 and '20 are connected to oppose cross magnetization and distortion of the field due to the load and and 30. An adjustment of the amount of magnetization or field strength and hence the power factor of the device is controllable by the manipulation of the adjustable rheostat 32. The direct current output or load is connected to the device on a circuit beginning at the brush 30, thence to the ring wound coils 17, located in the center of the slots 12 on the screen 1, and thence in succession to the ring wound coils 18, 19 and 20. tothe terminal L. The brush 27 is directly connected to the terminal L. When the load circuit LL is closed the ring wound coils 17, 18, 19 and 20 magnetize the screen ring 1, in opposition to the normal leakage and in proportion to the current on the load circuit carried by the machine, the magnetization produced by the ring wound coils being of the same polarity as the adjacent main pole faces. The operation in transforming from single phase alternating to direct current is substantially the same as described, with the addition of the usual phase splitting arrangement or the use of the commutator in series with a field coil in starting. The operation in transforming from direct current to alternating current comprises the usual methods used in starting a compound motor, the alternating current output being taken from the slip rings.

Although but one specific embodiment of this invention has been herein shown and de scribed, it will be understood that numerous details of the construction shown may be altered or omitted without rlepsrting from p screen arid arranged in sets interposed between adjacent poles, each set comprising form windings spaced apart, and ring windings locatedbetween them for the purpose specified.

2. In a device of the class described, an

annular magnetic screen member, formed and adapted to house and support the essential elements of asquirrel cage winding and having t ereon an annular series of slots spaced apart circumferentially, squirrel cage windings arranged on said screen to serve either as a damper or as induction armature circuits, a series of form windings mounted on said screen, said form windings being connected in series and disposed one adjacent to and lying partially within each side of said slots, and a series of ring windings mounted on said screen one being interposed between each pair of said form windings for the purpose specified. v

3. A magnetic screen for synchronous electric current converting machines, comprising an annular ring embodying squirrel cage construction, said ring having an annular series of spaced slots and having an annular series oi relatively narrow slots adjacent said first named slots, ring windings in said first named slots and form windings in said narrow slots, series connections for said ring windings with respect to the direct current line, and shunt connections for the form windings and adapted to control the position and amount of magnetism in said damper under varying conditions and load.

l. In a synchronous dynamo electric machine having a main field magnet system, an. armature and brushes for the armature, a magnetic screen disposed between the said armature and field magnet system and comprising an annular ring having squirrel cage members structurally embodied therein; said ring also having a series of slots symmetrically disposed therein, a system o windings mounted in said slots comprising ring windings and form windings arranged with the axes of adjacent ring and form windings substantially transverse to each other, respectively, and each kind being connected in a series by itself, connections for bringing one series of windings across the l'u'ushes i'tor control by potential of the machine and other means for connecting the second set of windings in series with the line for control by the load current of said machine, for the purpose specified.

In a device of the class described, a rigidly fixed annular magnetic screen, in combination with a damper o f squirrel cage crmstruction su 'iportcd and and a series ol" ring windings mounted on said screen for the purpose specified.

(i. In a device of the class described, the combination of main poles, field windings therefor, an armature, an armature windhoused thereby ing, a commutator, direct current brushes, collector rings, alternating current brushes, a fixed annular magnetic screen comprising a magnetic ring of squirrel age construction interposedbetween said armature and said poles, an annular series oi form windingsfmounted on said ring and connected in series between the field windings and one oi the direct current brushes, an annular series of ring windings spaced apart 0' arentially on said ring and inter-poses. at uniform intervals between said form windings for superimposing upon said screen ex ra magnetic flux, in opposition to the leakage flux, said ring windings being connected in series with the line connected to the direct current brushes for conducting unidirectional current transversely around said screen for controlling the position and amount of magnetism in said screen under various conditions of load.

7. In a device oi the class described, a magnetic screen comprising laminated ring having main and supplementary polar projections formed and spaced apart cir cumferentially ti'iereon, adjacent main polar projections being of opposite polarity, a se ries of windings arranged alternately in pairs of different polarity on said supplementary polar projections and connected to have supplementary poles of like polarity adjacent to the main poles of the same polarity and other windings interposed be tween the said windings in each said pairs for conducting unidirectional current transversely around said ring to control the position and amount of magnetism in said screen.

8. In a dynamo-electric machine, a magnet system comprising a yoke me n'ier having a plurality of magnetic poles synr metrically disposed and facing inward about a central axis, in combination with: a separate and continuous niiagnetic screen oi annular shape rigidly embraced by said poles and fitting tightly against the inner faces thereof, said screen comprising pliu'ality of annular magnetic lauunatious clamped together side by side. annular end plates for said screen. and a plurality o: traimvcrsely positioned bolts disposed in groups adjacent to said poles for clamping said end plates and laminations together, said end plates and bolts being of low electrical resistance and adapted to serve as an electric damp 9. In an electrical apparatus of the c '1 described, a rotary armature and a plurality of constantly excited stationary field poles of alternate polarity symmetricallydisposed about said urn'iature, in coml'iination with an annular nmgnctic screen fitting within and held rigidly in. place by said poles, and a series of supplementary poles provided and arranged in pairs on said screen substantially flush with the inner surface thereof and-adjacent opposite sides of said field and of like polarity therewith respectively.

11. In an electrical apparatus of the class described, a rotary armature and a plurality of constantly excited stationary field poles of alternate polarity symmetrically disposed about said armature in combination windings with a stationary annular magnetic screen interposed between said armature and said poles, and a-plurality of series ring windings symmetrically disposed on said screen between said poles and connected to oppose magnetic leakage, and to strengthen the fields. 1 a

12. Inan electrical apparatus ofthe class described, a rotary armature and a plurality of constantly excited stationary field poles of alternate polarity symmetrically disposed about said armature' in combination with a stationary annular magnetic screen interposed betweensaid armature and said poles, an annular series of supplementary poles formed on said screen in pairs adja-s cent to said main poles on opposite sides thereof and of like polarity therewith respectively, and a plurality of series ring symmetrically disposed on' said screen between said poles and connected to oppose magnetic leakage and to strengthen the fields.

13. In an electrical apparatus of the class described, a ro'tary)armature and a plurality of stationary field poles disposed symmetrically thereabout, in combination with a fixed annular magnetic screen interposed between said armature and poles, damper windings arranged opposite the pole faces and carried by said screen adjacent to the armature to oppose magnetic flux pulsations in the armature and field poles, .and series load to oppose mag coils arranged on said screen netic leakage through said screen. I

14. In an electrical apparatus of the class described, an armature and a field magnet system comprising a plurality of poles, arranged for relative rotation, in combination with a screen disposed between the said armature and poles and securely held by the latter, said screen having supplementary; poles adapted and arranged adjacent to the main poles to supplement and steady the flux of the main poles, exciting coils for said groups and spaced apart peripherally, each group being adjacent to one of said poles "respectively,

and magnetizing windingsdisposed on said sc'reenintermediately of adjacent groups of bars respectively, said screen being slotted transversely between said poles to receive said windings. v I

16. In a'converter of the character described, an armature member and a field member arranged for relative rotation, said field member having a plurality of poles and a screen disposed within and connecting the said poles, said screen carrying and housing damper windings disposed adjacent to ,thet said pol s, and also carrying regulating coils disposed intermediately of said poles.

17. In a device of the character described, a field system comprising an annular yoke having main poles, in combination with an annular magnetic screen mounted upon said poles, said screen bemg formed with a series of alternately arranged 1 ts and olar l a t ange o regprojections, the latter being a, ister with said main poles respectively, and electric windings in said slots.

Signed at Chicago this 16th day of July,

SAMUEL H. MARTIN; Witnesses:

PHILIP B. Woonwoa'rn, .EDWIN PHELPS. 

